A vertical situation display (“VSD”) provides a two-dimensional representation of an aircraft, the aircraft flight plan, and terrain under the aircraft or projected aircraft track. The VSD is usually displayed in close proximity to a lateral map display, such that the vertical situation of the aircraft can be coordinated visually with the lateral situation of the aircraft. In a practical deployment, the VSD may be included in a primary flight display, a multifunction display, or other suitable display component on the aircraft. VSD systems are designed to prevent controlled flight into terrain (“CFIT”) by providing a display of the terrain relative to the present altitude of the aircraft. In this regard, a member of the aircraft flight crew can obtain information related to the vertical situation of the aircraft relative to the terrain with a simple glance at the VSD.
Practical VSDs typically include a number of parameters and visual indicators that enable the pilot to form a quick mental picture of the vertical situation of the aircraft. For example, VSDs may include displays of an aircraft symbol, the aircraft altitude, the flight plan, the selected altitude, and the terrain. The physical space available to a VSD is usually limited, and the limited space should be efficiently allocated to accommodate the VSD elements.
Conventional VSD systems may not take full advantage of the display space allocated to the VSD. For example, at least one conventional VSD system considers only the origin and destination terrain elevations to determine the elevation of terrain displayed in the VSD. If, during flight, the altitude of the terrain under the aircraft falls below the origin/destination elevation, then the VSD will not include any terrain. When terrain is not displayed, such as in FIG. 1, it may be difficult for the pilot to form a mental picture of the vertical situation at a glance. On the other hand, when terrain 10 is displayed in a large portion of the available display 12, such as in FIG. 2, much of the vertical display range is utilized to show more terrain than is necessary to enable the pilot to form a mental picture of the current vertical situation. Furthermore, the display of excess terrain may preclude the display of other parameters or additional information of interest at the top of the VSD, such as the flight plan or the selected altitude (not shown in FIG. 2).
Accordingly, it is desirable to have a VSD system that automatically positions the terrain and/or adjusts the vertical scale of the display such that terrain is in view if practical and such that the vertical range of the VSD is efficiently utilized. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.